At their general meeting in Prague on August 24, 2006, the IAU membership voted to strip Pluto of its planetary status, making it a member of a new class of objects called “Dwarf Planets.” The solar system is now left with only eight planets, and an indeterminate number of smaller objects such as asteroids, comets, and KBOs, which will now be called “Small Solar System Objects.”
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In voting to scratch Pluto from the ranks of true solar planets the IAU rejected a proposal drawn up by special “Planet Definition” committee set up by the organization. The committee’s proposal would have recognized 12 planets in the solar system right now, with dozens of other planets likely to join the ranks in the coming years. The old nine-planet neighborhood we have grown accustomed to would have been replaced by a frequently changing crowd of planetary strangers. Instead, the IAU chose to eliminate the most questionable member of the planetary club and fix the number of solar planets once and for all on eight.
I think they made the right decision.